Material interface detection based on secondary electron images for focused ion beam machining.

A method for interface detection is proposed for focused ion beam (FIB) processes of multilayered targets. As multilayers have emerged as promising structures for nanodevices, the FIB machining of multilayers has become a challenging issue. We proposed material interface detection by monitoring secondary electron (SE) images captured during the FIB process.

Contact Effect of ReS/Metal Interface.

Rhenium disulfide (ReS) has attracted immense interest as a promising two-dimensional material for optoelectronic devices owing to its outstanding photonic response based on its energy band gap's insensitivity to the layer thickness. Here, we theoretically calculated the electrical band structure of mono-, bi-, and trilayer ReS and experimentally found the work function to be 4.8 eV, which was shown to be independent of the layer thickness.

Layer dependence and gas molecule absorption property in MoS2 Schottky diode with asymmetric metal contacts.

Surface potential measurement on atomically thin MoS2 flakes revealed the thickness dependence in Schottky barriers formed between high work function metal electrodes and MoS2 thin flakes. Schottky diode devices using mono- and multi-layer MoS2 channels were demonstrated by employing Ti and Pt contacts to form ohmic and Schottky junctions respectively. Characterization results indicated n-type behavior of the MoS2 thin flakes and the devices showed clear rectifying performance.

A high throughput supra-wavelength plasmonic bull's eye photon sorter spatially and spectrally multiplexed on silica optical fiber facet.

This paper presents a plasmonic bull's eye consisting of a micron-sized hole and a concentric nano-antenna metallic ring surrounded by periodic circular grooves on a thin gold film. The unique metallic nano-ring imbedded in the supra-wavelength-sized hole acts as an amplifying and filtering component to simultaneously provide a significantly lower spectral noise and a higher power transmission at the resonance wavelength, in comparison to prior sub-wavelength bull's eyes. Systematic numerical analyses based on finite-difference time-domain method were carried out to find the impacts of the structural parameters.

Synthesis and bidirectional frequency tuning of cantilever-shape nano resonators using a focused ion beam.

The synthesis of cantilever-shape nano resonators and their resonant frequency tunings in both upward and downward directions have been demonstrated using FIB-CVD (focused ion beam-chemical vapor deposition). The in situ experimental observations of mechanical resonances as well as cutting and adding of resonator materials have been accomplished inside the FIB vacuum chamber. Extending the length of the cantilever-shape resonator by 500 nm scale using either the same material or alternating different materials effectively reduced resonant frequency.

Spatially discrete thermal drawing of biodegradable microneedles for vascular drug delivery.

Spatially discrete thermal drawing is introduced as a novel method for the fabrication of biodegradable microneedles with ultra-sharp tip ends. This method provides the enhanced control of microneedle shapes by spatially controlling the temperature of drawn polymer as well as drawing steps and speeds. Particular focus is given on the formation of sharp tip ends of microneedles at the end of thermal drawing.

Fabrication of ordered bulk heterojunction organic photovoltaic cells using nanopatterning and electrohydrodynamic spray deposition methods.

Organic photovoltaic cells with an ordered heterojunction (OHJ) active layer are expected to show increased performance. In the study described here, OHJ cells were fabricated using a combination of nanoimprinting and electrohydrodynamic (EHD) spray deposition methods. After an electron donor material was nanoimprinted with a PDMS stamp (valley width: 230 nm, period: 590 nm) duplicated from a Si nanomold, an electron acceptor material was deposited onto the nanoimprinted donor layer using an EHD spray deposition method.

The fabrication of metal silicide nanodot arrays using localized ion implantation.

We propose a process for fabricating nanodot arrays with a pitch size of less than 25 nm. The process consists of localized ion implantation in a metal thin film on a Si wafer using a focused ion beam (FIB), followed by chemical etching. This process utilizes the etching resistivity changes of the ion beam irradiated region that result from metal silicide formation by ion implantation.